How to get the average of a nested query returned as a single result based on the parent query
Here is another problem I have had to deal with in the last couple of days. I have the following query:
SELECT S.Name,S.Surname,S.Student_ID,S.StudentNumber,C.Course, B.Campus_Title,M.Module,SM.Percentage_Obtained,S.Days_Absent
FROM Students S
INNER JOIN Student_Courses SC
ON SC.StudentID = S.ID
INNER JOIN Courses_Te开发者_开发百科mplate C
ON C.ID = SC.courseID
INNER JOIN Branches B
ON B.ID = S.BranchID
INNER JOIN Student_Modules SM ON
SM.StudentID =S.ID
INNER JOIN Modules_Template M ON
M.ID = SM.ModuleID
The problem is that I want to rewrite the query to get a calculated result like this:
SELECT S.Name,S.Surname,S.Student_ID,S.StudentNumber,C.Course, B.Campus_Title,M.Module,SM.Percentage_Obtained,S.Days_Absent,
(SELECT AVG(Percentage_Obtained)
FROM Student_Modules
INNER JOIN Courses_Template
ON Courses_Template.ID = Student_Modules.CourseID
INNER JOIN Modules_Template
ON Courses_Template.ID = Modules_Template.CourseID
WHERE Modules_Template.Module= M.Module)[AS Class Average]
FROM Students S
INNER JOIN Student_Courses SC
ON SC.StudentID = S.ID
INNER JOIN Courses_Template C
ON C.ID = SC.courseID
INNER JOIN Branches B
ON B.ID = S.BranchID
INNER JOIN Student_Modules SM ON
SM.StudentID =S.ID
INNER JOIN Modules_Template M ON
M.ID = SM.ModuleID
The Original Values for the modules is (extracted)
M.Modules AVG(Percentage_Obtained)
Module 1 99
Module 2 98
Module 3 94
Module 1 94
Module 2 22
Module 3 100
The expected Results that I wanted from the second query was this
M.Modules AVG(Percentage_Obtained) (SubQuery's Average)
Module 1 99 97
Module 2 98 60
Module 3 94 96
Module 1 94 97
Module 2 22 60
Module 3 100 96
however, what it gave to me was something completely different
The expected Results that I wanted from the second query was this
M.Modules AVG(Percentage_Obtained) (SubQuery's Average)
Module 1 99 84
Module 2 98 84
Module 3 94 84
Module 1 94 84
Module 2 22 84
Module 3 100 84
Can anyone perhaps spot my mistake from somewhere? I need all of these fields in a single query, because I must make a report on it. The sub query's results is crucial
Its almost like I need this (but Dynamically for All recurrences of a Module):
SELECT AVG(Percentage_Obtained)
FROM Student_Modules
INNER JOIN Modules_Template ON Modules_Template.ID = Student_Modules.ModuleID
WHERE Modules_Template.Module = 'Module 1' -- And module 2, and module 3 .... but Dynamically
You can try the following query:
SELECT S.Name,S.Surname,S.Student_ID,S.StudentNumber,C.Course, B.Campus_Title,M.Module,SM.Percentage_Obtained,S.Days_Absent, SM2.AvgPercentage_Obtained
FROM Students S
INNER JOIN Student_Courses SC
ON SC.StudentID = S.ID
INNER JOIN Courses_Template C
ON C.ID = SC.courseID
INNER JOIN Branches B
ON B.ID = S.BranchID
INNER JOIN Student_Modules SM ON
SM.StudentID =S.ID
INNER JOIN Modules_Template M ON
M.ID = SM.ModuleID
OUTER APPLY (SELECT AVG(Percentage_Obtained) AvgPercentage_Obtained
FROM Student_Modules
INNER JOIN Modules_Template ON Modules_Template.ID = Student_Modules.ModuleID
WHERE Student_Modules.Module = M.Module) SM2
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